In this image taken from video and released by SITE Intelligence Group on Nov. 8, 2010, Anwar al-Awlaki speaks in a video message posted on radical websites. A federal judge is throwing out a lawsuit aimed at preventing the US from assassinating the US-born cleric.

Washington — A federal judge in Washington ruled on Tuesday that he lacks the authority to hear a lawsuit that sought to block the US government from carrying out the targeted killing of an American citizen hiding in Yemen who is suspected of involvement in terror operations.

The suit asked the judge to issue an injunction prohibiting the Central Intelligence Agency and Defense Department from intentionally killing Mr. Awlaki unless the government could first demonstrate that he posed an imminent threat to life or safety, and that no nonlethal means were available to meet the threat.

Judge Bates said the suit must be dismissed under the political question doctrine, which requires judges to step aside in issues that are best resolved by the elected, political branches of government.

He also ruled that Awlaki’s father, Nasser, lacked the necessary legal standing to litigate the case on his son’s behalf in a US court.

The litigation has attracted attention because it poses stark questions about the limits of constitutional protections of American citizens in national security cases.

Critics question whether the government can order the assassination of a US citizen without first affording him any form of judicial process, based entirely on the government’s assertion that he is a dangerous member of a terrorist organization. They also question how it is that the government is required to obtain court approval before conducting electronic surveillance of an American citizen overseas, yet judicial oversight is inappropriate when the government identifies that same citizen for targeted killing.

Judge Bates did not confront those central questions in his dismissal order, throwing the case out on procedural grounds. But he acknowledged that questions remain.

“The court recognizes the somewhat unsettling nature of its conclusion – that there are circumstances in which the Executive’s unilateral decision to kill a US citizen overseas is constitutionally committed to the political branches and judicially unreviewable,” Bates wrote in his 83-page decision. “But this case squarely presents such a circumstance.”

He added that the political question doctrine “does not contain any ‘carve-out’ cases involving the constitutional rights of US citizens.”

“If the court’s ruling is correct, the government has the unreviewable authority to carry out the targeted killing of any American, anywhere, whom the president deems to be a threat to the nation,” Jameel Jaffer, deputy legal director of the ACLU, said in a written statement. “It would be difficult to conceive of a proposition more inconsistent with the Constitution or more dangerous to American liberty.”

“It is wholly proper for the American military to be making plans to defeat Al Qaeda by eliminating its military leaders,” Mr. Samp said. “Anwar al-Awlaki is a leader of an Al Qaeda affiliate. His US citizenship does not entitle him to an exemption from the normal rules of war.”

He is suspected of assisting in the attempted Christmas Day bombing of a commercial jetliner near Detroit. He is also considered an effective recruiting asset for Al Qaeda among Muslims in the US.

Awlaki has never been publicly charged with a crime. It remains unclear what criteria the Obama administration has used to determine that he should be killed.

Bates acknowledged that it is a “drastic measure” for the government to use lethal force against one of its own citizens. But he said it is up to the policymaking branches of government to decide when “drastic measures” should be taken.

“This Court does not hold that the Executive possesses unreviewable authority to order the assassination of any American whom he labels an enemy of the state,” Bates wrote. “Rather, the Court only concludes that it lacks the capacity to determine whether a specific individual in hiding overseas, whom the director of national intelligence has stated is an ‘operational’ member of [Al Qaeda on the Arabian Peninsula], presents such a threat to national security that the United States may authorize the use of lethal force against him.”

Bates said judges are “functionally ill-equipped to make the types of complex policy judgments that would be required to adjudicate” such a case.

He said the case would require him to “understand and assess the capabilities of the [alleged] terrorist operative to carry out a threatened attack, what response would be sufficient to address that threat, possible diplomatic considerations that may bear on such responses, the vulnerability of potential targets that the [alleged] terrorist may strike, the availability of military and nonmilitary options, and the risks to military and nonmilitary personnel in attempting application of non-lethal force.”

In finding that Awlaki’s father lacked standing to bring the lawsuit, Bates said that it appears that the son could have filed a lawsuit on his own behalf, but has declined to do so.

He cited statements and recorded messages that have appeared in recent months – including a vow from Awlaki that he would never surrender to American authorities.

“The fact that [Awlaki] has not brought suit during the past 10 months that his name has allegedly appeared on ‘kill lists’ strongly suggests that his rights are either not truly at stake or not truly important to him,” the judge said.

Bates said Awlaki himself holds the key to preventing the US from moving forward with its alleged “kill list” plan. He said Awlaki, like any other US citizen, could avail himself of the protections of the US judicial system.

But the judge added: “No US citizen may simultaneously avail himself of the US judicial system and evade US law enforcement authorities.”

“[Awlaki] would not be killed if he were to present himself in a peaceful manner and seek relief in the US courts,” Bates wrote. The judge recognized the drawback in this course of action for Awlaki. “He would expose himself to possible detention as an enemy combatant,” the judge acknowledged.